This invention relates to semiconductor manufacturing technology, and in particular to an effective technology that is applicable to improving temperature-cycling characteristics.
In recent years, higher densities of mounting have been accompanied by a requirement for more compact and thinner semiconductor products. As a technology in response to this requirement, Patent Official Gazette 11-74440 discloses a resin-molded type semiconductor device and a method for manufacturing it in which the tub on which the semiconductor chip is mounted is elevation processed (processed to elevate the tub).
In the semiconductor device described in Patent Official Gazette 11-74440, the leads are located at the periphery of the back surface (semiconductor device mounting surface) of a molded section, the tub is set higher than the leads by bending the suspension leads, and molding resin is provided on the back surface of the tub. Accordingly, the tub is embedded in molding resin, thus achieving high degrees of reliability and thinness.
However, in a semiconductor device in the configuration described in Patent Official Gazette 11-74440, although molding resin is provided on the back surface of the tub, the tub is lifted by bending of the suspension leads alone (elevation processing). As a result, a step is generated between the leads and the tub, and the chip is set higher.
Therefore, the semiconductor device described in Patent Official Gazette 11-74440 is not capable of achieving sufficient thinness.
If the molding resin on the back surface of the tub is made thinner or eliminated (tub-exposed configuration), the balance between the molding resin above and below the semiconductor chip (resin balance) deteriorates. Applying temperature cycling to such a semiconductor device causes cracks in its package.
One objective of this invention is to provide a semiconductor device such that cracking of its package is prevented and a method of manufacturing this device.
Another objective of this invention is to provide a semiconductor device and a method for manufacturing it that achieves thinness while maintaining the balance between the resin above and below the semiconductor chip.
The objectives and novel features of this invention will be clarified by the following description of its specifications and by the accompanying drawings.
A typical example of the invention disclosed in this application is briefly summarized in the following passage.
A semiconductor device of this invention comprises:
a tub that supports a semiconductor chip;
a molded section that is formed by molding resin around the semiconductor chip;
suspension leads, including a supporting portion that supports the tub and an exposed portion that is connected to the supporting portion and is exposed at the surface of the molded section where the semiconductor device is mounted, that are processed so that the supporting portion is elevated;
leads that are placed around the tub and are exposed at the surface of the molded section where the semiconductor device is mounted; and
thin metal wires that connect the electrodes of the semiconductor chip with the corresponding leads;
wherein the tub and the supporting portions of the suspension leads are thinner than the exposed portion, and the major surface and part of the opposite surface of the semiconductor chip are in firm contact with the molding resin.
This invention makes a thicker molded section below the back surface of the tab possible, it thus eliminates differences in thickness between the molded sections above (major surface) and below (back surface) the semiconductor chip. Therefore, the balance between the amounts of molding resin above and below the semiconductor chip (resin balance) can be improved, and reduces the amount of stress applied to the embedded sections below the semiconductor chip during temperature cycling.
In addition, since part of the back surface of the semiconductor chip is in firm contact with the molding resin, it is possible to improve the degree of adhesion between the semiconductor chip and the molding resin on the back surface of the semiconductor chip. Cracking of the package can thus be prevented since the balance between the amounts of resin above and below the semiconductor chip is improved as is the degree of adhesion, on the back surface of the semiconductor chip, between the semiconductor chip and the molding resin; the device""s temperature-cycling characteristics are thus improved.
A semiconductor device of this invention is comprised of:
a tub as a supporting part for the opposite surface of the major surface of a semiconductor chip;
a molded section formed by resin-molding around the semiconductor chip;
suspension leads, including supporting portions that support the tub and exposed portions that are connected to the supporting portions and are exposed on the surface of the molded section within which the semiconductor device is mounted, and being deformed so that the supporting portion is displaced away from the exposed surface of the exposed portion;
leads that are located around the tub and are exposed on the surface of the molded section within which the semiconductor device is mounted; and
thin metal wires that connect the electrodes of the semiconductor chip with the corresponding leads;
wherein the tub and the supporting portions of the suspension leads are thinner than the exposed portion, and the major surface and part of the opposite surface of the semiconductor chip are firmly in contact with the molding resin.
A semiconductor device of this invention comprises:
a tub smaller than a semiconductor chip, which supports the semiconductor chip;
a molded section formed by resin-molding around the semiconductor chip;
suspension leads, including supporting portions that support the tub and an exposed portion that is connected to the supporting portion and is exposed at the surface of the molded section where the semiconductor device is mounted, that are processed so that the supporting portion is elevated;
leads that are located around the tub and are exposed to the semiconductor device mounting surface of the molded section; and
thin metal wires that connect the electrodes of the semiconductor chip with the corresponding leads;
wherein the tub and the supporting portions of the suspension leads are thinner than the exposed portion, and the major surface and part of the opposite surface of the semiconductor chip are firmly in contact with the molding resin.
A method of manufacturing a semiconductor device of this invention is comprised of the steps of:
forming a leadframe which has
a tub to support a semiconductor chip, suspension leads that include supporting portions which support the tub and exposed portions that are connected to the supporting portionsxe2x80x94the supporting portions of which are upsetxe2x80x94processed, and leads that are located around the tub, where the tub and supporting portions are made thinner than the exposed portions;
bonding the tub and semiconductor chip;
using thin metal wires to connect the electrodes of the semiconductor chip with the corresponding leads;
forming a molded section where molding resin is provided on the surface opposite the chip-supporting portion of the tub, the major surface and part of the opposite surface of the semiconductor chip are firmly brought into contact with the molding resin, the leads and the exposed portions of the suspension leads are on the same surface as the mounting for the semiconductor device, and resin-molding is around the semiconductor chip; and
separating the leads and the suspension leads, at the exposed portions of the suspension leads, from the frame portion of the leadframe.
A method of manufacturing a semiconductor device of this invention is comprised of the steps of:
forming a leadframe which has
a tub to support a semiconductor chip, suspension leads that include supporting portions which support the tub and exposed portions which are connected to the supporting portionsxe2x80x94the suspension leads are deformed to displace the chip-supporting portion away from the surface where the exposed portions are exposed, and leads that are located around the tub, where the tub and supporting portions are made thinner than the exposed portions;
bonding the tub to part of the surface of the semiconductor chip that is opposite the chip""s major surface;
using thin metal wires to connect the electrodes of the semiconductor chip with the corresponding leads;
forming a molded section where molding resin is provided on the surface opposite the chip-supporting portion of the tub, the major surface and part of the opposite surface of the semiconductor chip are firmly brought into contact with the molding resin, the leads and the exposed portions of the suspension leads are on the same surface as the mounting for the semiconductor device, and resin-molding is around the semiconductor chip; and
separating the leads and the suspension leads, at the exposed portions of the suspension leads, from the frame section of the leadframe.
A semiconductor device of this invention is comprised of:
a chip-mounting portion with major and back surfaces;
supporting leads with major and back surfaces, which are linked to the chip-mounting section;
leads located around the chip-mounting section;
a semiconductor chip with a major surface on which the semiconductor elements and bonding pads are formed and a back surface (opposite surface) that is made to adhere to the surface of the chip-mounting section;
bonding wires that electrically connect the bonding pads and the leads; and
resin on the upper and back (opposite) surfaces, which is molded around the chip-mounting portion, the supporting leads, the leads, the semiconductor chip, and the bonding wires;
wherein
parts of the leads are exposed on the back surface of the resin;
the chip-mounting portion is smaller than the semiconductor chip;
the chip-mounting portion is shallower than the leads; and
the surface of the chip-mounting portion is higher than the upper surfaces of the parts of the leads that are exposed on the back surface of the resin.